JP2008190472A - Cylinder block and cylinder liner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylinder block capable of inhibiting bore deformation during engine actual operation and preventing deterioration of circularity of a cylinder bore during engine actual operation without increasing processes in finishing process such as horning of the cylinder bore of the cylinder block. <P>SOLUTION: The cylinder block 1 includes the cylinder bore 4 opening on a head mounting surface 3 on which a cylinder head is fixed by head bolts 11, and a water jacket 6 formed to surround the cylinder bore 4 via a cylinder part 5 which is a wall shape part surrounding the cylinder bore 4. Depressed parts 21, 22 at least in a height range of the water jacket 6 are provided on a section of a phase out of the phase (angle range α1) corresponding to a bolt fastening part 10 of a circumference shape of the cylinder bore 4 out of a liner outer circumference surface 19 and a cylinder part outer circumference surface 15 receiving cooling effect by the water jacket 6. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cylinder block constituting an internal combustion engine such as an automobile engine, and a cylinder bore for forming a cylinder bore in the cylinder block.

For example, in a cylinder block that constitutes an internal combustion engine such as an automobile engine, as a general configuration, a cylinder bore that is a cylindrical hole portion in which a piston is slidably housed, and a surface on which the cylinder bore opens and a cylinder And a cylinder head mounting surface (hereinafter simply referred to as “head mounting surface”) on which the head is assembled. When the cylinder head is assembled to the head mounting surface, a fastener (head bolt) such as a bolt is used. That is, the cylinder head is fastened and fixed to the cylinder block by screwing the head bolt into the bolt hole that penetrates the cylinder head and forms a female screw portion provided in the cylinder block.
A bolt hole into which a head bolt is screwed when the cylinder head is fixed to the cylinder block is provided around the cylinder bore on the head mounting surface. Specifically, there is a configuration in which four are provided at substantially equal intervals around the cylinder bore. In other words, in this case, for example, in an in-line four-cylinder engine mounted on an automobile or the like, two bolt holes are shared between adjacent cylinder bores for four cylinder bores arranged in a row, A total of 10 bolt holes will be provided.

  In such a configuration, deformation of the cylinder bore (bore deformation) occurs when the cylinder head is assembled to the cylinder block and when the engine configured by using the cylinder block is operated, and the roundness of the cylinder bore is deteriorated. Is a problem. These bore deformations will be specifically described with reference to FIG. FIG. 13 is a schematic diagram showing the arrangement of bolt fastening portions with respect to the cylinder bore and conventional bore deformation, (a) showing a single product state (non-assembled state), and (b) showing bore deformation at the time of assembly. FIG. 5C is a diagram showing bore deformation during engine operation.

As shown in FIG. 13, as an example of arrangement of the bolt fastening portion for fixing the cylinder head to the cylinder block with respect to the cylinder bore, four bolt fastening portions 110 are arranged at substantially equal intervals around the cylinder bore 104 with respect to one cylinder bore 104. There is a configuration provided. In each bolt fastening portion 110, the head bolt 111 is screwed into the bolt hole 112 formed in the cylinder block.
As shown in FIG. 13A, when the cylinder head is not fixed by tightening the head bolt 111 screwed into the bolt hole 112, the tightening force (fastening force) by the head bolt 111 is applied to the cylinder block. Since it is not applied to the cylinder block, the cylinder block is not deformed by the tightening force acting, and the cylinder bore 104 is not deformed.

As shown in FIG. 13B, when the head bolt 111 is tightened and the cylinder head is fastened and fixed to the cylinder block, the tightening force by the head bolt 111 acts on the cylinder block. However, this tightening force causes the cylinder block to be deformed, resulting in bore deformation. The bore deformation (hereinafter referred to as “assembly deformation”) that occurs when the cylinder head is assembled is caused by strongly pressing the upper surface of the bore (the peripheral edge of the cylinder bore 104 on the head mounting surface) by tightening the head bolt 111.
Accordingly, the deformation is increased around the bolt that is particularly strongly pressed, and in the configuration in which four bolt fastening portions 110 are provided at substantially equal intervals around the cylinder bore 104 as in this example, the bolt fastening is performed at the cylinder bore 104. A portion of the phase corresponding to the portion 110 (hereinafter referred to as a “bolt phase”) is deformed so as to be constricted inward (relatively bulging inward). As a result, as shown in FIG. 13B, the assembly deformation is such that the cylinder bore 104 that is circular in plan view has a cross shape (so-called quaternary deformation).

Further, in the actual operation of the engine configured by using the cylinder block in which the cylinder head is assembled by the head bolt 111 as described above, in addition to the above-described assembly deformation, thermal expansion and heat during the actual operation of the engine are performed. There is bore deformation (hereinafter referred to as “thermal deformation”) caused by thermal load (thermal stress) such as strain.
As shown in FIG. 13C, the thermal deformation that occurs during actual operation of the engine is a deformation in which the cross shape is emphasized in the assembled cylinder bore. This is due to the following reason. That is, during actual operation of the engine, the temperature of the cylinder block rises and the cylinder bore expands in the circumferential direction. At this time, the deformation of the bolt phase portion is suppressed by the bolt axial force due to the fastening of the head bolt. For this reason, as indicated by an arrow in FIG. 13C, the portion other than the bolt phase in the cylinder bore 104 expands more than the portion of the bolt phase, and the bore deformation is a deformation that emphasizes the cross shape. Become.

Such bore deformation deteriorates the roundness of the cylinder bore. Deterioration of the roundness of the cylinder bore due to thermal deformation during engine operation including assembly deformation causes an increase in friction (sliding resistance) due to sliding of the piston in the cylinder bore. The increase in friction causes the output of the internal combustion engine to be limited and the fuel consumption to deteriorate.
That is, when a piston ring that slides against the cylinder bore is attached to the piston, when the roundness of the cylinder bore deteriorates, a portion that deforms from a perfect circle to a large diameter (expanded portion) in the cylinder bore is sealed by the piston ring. The engine oil consumption and blow-by gas increase due to leaching. This situation is avoided by increasing the piston ring tension (the force to expand) (increasing the tension) so that the minimum pressing force by the piston ring can be secured even at the part where the cylinder bore changes to a large diameter. be able to. However, increasing the tension of the piston ring causes an increase in overall friction in the cylinder bore.

Thus, as a technique for suppressing the deterioration of the roundness of the cylinder bore due to the bore deformation, which causes the above-described problems, there is a technique described in Patent Document 1, for example.
This document discloses a method in which a cylinder block is heated to a predetermined temperature when a finishing process (honing process) for obtaining a predetermined roundness is performed on a cylinder bore of the cylinder block.
That is, the cylinder block is heated to a predetermined temperature, so that the cylinder block is brought to a temperature state as when the engine is actually operated, and then honing is performed on the cylinder bore. Thereby, since the roundness of the cylinder bore is ensured in a state where the cylinder block is thermally expanded (thermally deformed state), an effect of improving the roundness of the cylinder bore during engine operation can be obtained.

However, in the technology disclosed in Patent Document 1, a process for heating the cylinder block is separately required in processing for obtaining a predetermined roundness of the cylinder bore in the cylinder block. An increase in the number of processing steps is not preferable for improving mass productivity.
JP 2004-36511 A

  The present invention has been made in view of the problems of the prior art as described above, and the problem to be solved is not accompanied by an increase in the number of steps in finishing processing such as honing for the cylinder bore of the cylinder block. An object of the present invention is to provide a cylinder block and a cylinder liner that can suppress bore deformation that occurs during actual operation of the engine and that can prevent deterioration of the roundness of the cylinder bore during actual operation of the engine.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, according to the present invention, a cylinder bore that is a cylindrical hole that opens to a cylinder head mounting surface to which a cylinder head is fixed by a fastening member and slidably houses a piston, and a wall-shaped portion that surrounds the cylinder bore A cylinder block having a water jacket formed so as to surround the cylinder bore via a bore forming portion including a certain cylinder portion, and the cylinder bore among the surfaces of the bore forming portion that receives a cooling action by the water jacket. A concave portion is provided at least in the height range of the water jacket in a phase portion other than the phase corresponding to the fastening portion by the fastening member in the circumferential shape.

  According to a second aspect of the present invention, the cylinder bore is formed by a cylindrical cylinder liner, and includes an outer peripheral surface of the cylinder liner on a surface of the bore forming portion that receives the cooling action.

  5. A cylinder bore as a cylindrical hole portion formed in a cylindrical cylinder liner and open to a cylinder head mounting surface to which a cylinder head is fixed by a fastening member, and a cylinder as a wall portion surrounding the cylinder bore. A cylinder block having a water jacket formed so as to surround the cylinder bore via a portion, in a portion of the phase corresponding to the fastening portion by the fastening member in the circumferential shape of the cylinder bore of the cylinder liner, An air layer is provided at least in the height range of the water jacket.

  According to a fourth aspect of the present invention, the air layer is cast into the cylinder liner, and a space forming member made of a material having a smaller linear expansion coefficient than a material constituting the cylinder liner is cast into the cylinder liner. Thus, the space is formed by a difference in cooling shrinkage between the material portion constituting the cylinder liner and the space forming member.

  6. A cylinder bore that is a cylindrical hole portion that opens to a cylinder head mounting surface to which a cylinder head is fixed by a fastening member and slidably houses a piston, and a cylinder that is a wall-like portion surrounding the cylinder bore A cylinder block having a water jacket formed so as to surround the cylinder bore via a portion, and a phase other than a phase corresponding to a fastening portion by the fastening member in a circumferential shape of the cylinder bore among the cylinder portion Is provided with fins made of a material having higher thermal conductivity than the material constituting the main body of the cylinder block at least in the height range of the water jacket.

  7. A cylindrical cylinder liner that forms a cylinder bore that opens to a cylinder head mounting surface to which a cylinder head is fixed by a fastening member in a cylinder block, and the circumferential shape of the cylinder bore in an outer peripheral surface A concave portion is provided at least in the height range of the water jacket in a phase portion other than the phase corresponding to the fastening portion by the fastening member.

  In Claim 7, It is a cylindrical cylinder liner which forms the cylinder bore opened to the cylinder head mounting surface to which a cylinder head is fixed with a fastening member in a cylinder block, Comprising: By the fastening member in the circumference shape of the cylinder bore An air layer is provided in the phase portion corresponding to the fastening portion at least in the height range of the water jacket.

  In the present invention, the air layer is cast into the cylinder liner, and a space forming member made of a material having a smaller linear expansion coefficient than a material constituting the cylinder liner is cast into the cylinder liner. Thus, the space is formed by a difference in cooling shrinkage between the material portion constituting the cylinder liner and the space forming member.

As effects of the present invention, the following effects can be obtained.
That is, according to the present invention, it is possible to suppress the bore deformation that occurs during engine operation without increasing the number of steps in finishing processing such as honing for the cylinder bore of the cylinder block, and the roundness of the cylinder bore during engine operation. Can be prevented.

Next, embodiments of the invention will be described.
The cylinder block according to the present invention constitutes an internal combustion engine such as an automobile engine, for example, and is opened in a cylinder head mounting surface to which the cylinder head is fixed by a fastening member (head bolt) and is slidably provided with a piston. It has a cylinder bore which is a cylindrical hole, and a water jacket which is formed so as to surround the cylinder bore via a cylinder which is a wall-like portion surrounding the cylinder bore.
Further, according to the present invention, at the time of engine operation, the temperature of the phase (bolt phase) corresponding to the fastening portion by the head bolt in the peripheral portion of the cylinder bore including the cylinder portion is relative to other phase portions. This increases the thermal expansion of the bolt phase portion and prevents the roundness of the cylinder bore from deteriorating during engine operation.

That is, during bore deformation (thermal deformation) that occurs during engine operation, deformation of the bolt phase portion is suppressed by the bolt axial force due to fastening of the head bolt. For this reason, the portion of the phase other than the bolt phase expands more than the portion of the bolt phase, and the roundness deteriorates. Therefore, as described above, the temperature of the bolt phase portion is made relatively higher than that of the other phase portions, and the thermal expansion is increased, so that the bore deformation (bore expansion) becomes uniform, and the engine is in operation. The roundness of the cylinder bore can be improved.
Hereinafter, each embodiment of the cylinder block according to the present invention having a configuration for making the temperature of the bolt phase portion relatively higher than the other phase portions will be described.

  A first embodiment of a cylinder block according to the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a configuration of a cylinder block according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 3 is a view showing a cylinder liner according to the first embodiment of the present invention. 4 is a cross-sectional view taken along the line BB in FIG.

As shown in FIGS. 1 and 2, the cylinder block 1 according to the present embodiment has a cylinder body made of aluminum and a cylinder head 2 fixed by a head bolt 11 (FIG. 2) as a fastening member. A head mounting surface (hereinafter referred to as “head mounting surface”) 3, a cylinder bore 4 that is a cylindrical hole that opens in the head mounting surface 3 and slidably houses a piston 7, and a wall that surrounds the cylinder bore 4 And a water jacket 6 formed so as to surround the cylinder bore 4 via a bore forming portion 14 including the cylinder portion 5 which is a cylindrical portion.
The cylinder block 1 according to the present embodiment constitutes a multi-cylinder engine such as an in-line four-cylinder engine and the like, and includes a plurality of cylinder bores 4 (four in the case of four cylinders). It arrange | positions in a row in the adjacent state so that a direction may become parallel (refer FIG. 2 etc.).

The head mounting surface 3 is a sealing surface formed as a flat surface on one side of the cylinder block 1, and the cylinder head 2 is assembled to the head mounting surface 3 through a gasket or the like. As shown in FIG. 2, when the cylinder head 2 is assembled to the head mounting surface 3, the head bolt 11 is used as described above. That is, the head bolt 11 penetrates the cylinder head 2 and is screwed into the bolt hole 12 serving as a female screw portion provided in the cylinder block 1, whereby the cylinder head 2 is fastened and fixed to the cylinder block 1.
A bolt fastening portion 10 as a fastening portion used for fixing the cylinder head 2 to the cylinder block 1, that is, a bolt hole 12 into which the head bolt 11 is screwed, is provided around the cylinder bore 4 on the head mounting surface 3. In the present embodiment, as shown in FIG. 2, four cylinders are provided around the cylinder bore 4 at substantially equal intervals. In addition, two bolt holes 12 are shared between adjacent cylinder bores 4. That is, in this case, for example, in a cylinder block constituting an in-line four-cylinder engine, a total of ten bolt holes 12 are provided for four cylinder bores arranged in a line.
An oil pan (not shown) is attached to the cylinder block 1 on the side opposite to the head attachment surface 3. Hereinafter, in the cylinder block 1, the side on which the cylinder head 2 is assembled is referred to as “upper”, and the opposite side is referred to as “lower”.

As shown in FIG. 1, a plurality of cylinder bores 4 are arranged as described above with the central axis direction as the vertical direction. A piston ring 8 is attached to the piston 7 housed in the cylinder bore 4. The piston 7 slides back and forth in the cylinder bore 4 through the piston ring 8 in the vertical direction.
The space above the piston 7 in each cylinder bore 4 constitutes a part of a combustion chamber for burning a fuel / air mixture. The cylinder bore 4 is formed on a cylindrical surface having a predetermined roundness by a finishing process such as a honing process in order to keep the air-fuel mixture and gas generated by combustion confidential. That is, during actual operation of an engine manufactured using the cylinder block 1, the biston 7 reciprocates and slides due to the explosion and combustion of the air-fuel mixture in the combustion chamber, thereby causing the piston 7 and the connecting rod (connecting rod) to pass through. The connected crankshaft (output shaft) rotates.

The cylinder bore 4 has a cylinder liner 9 formed of a cast iron as a material on the inner peripheral surface side of the cylinder portion 5 formed in a substantially cylindrical shape so as to correspond to each cylinder bore 4 in the cylinder block 1. It is formed by being installed by press fitting or the like. That is, the inner peripheral surface of the cylinder liner 9 forms the cylinder bore 4 and becomes the sliding surface of the piston 7. As described above, in the present embodiment in which the cylinder bore 4 is formed by using the cylinder liner 9, the bore forming portion 14 includes the cylinder portion 5 and the cylinder liner 9.
In this embodiment, the cylinder bore 4 is formed by using the cylinder liner 9, but the cylinder bore is a structure of the cylinder block, for example, when the cylinder block is made of an iron-based material such as cast iron. The structure formed directly may be sufficient.

The water jacket 6 is a passage for the cooling water 6 a and is formed so as to surround the plurality of cylinder bores 4 when the cylinder block 1 is cast. The water jacket 6 is provided to the cylinder bore 4 via the cylinder portion 5.
The cylinder portion 5 is a cylindrical wall-shaped portion formed so as to surround the cylinder bore 4 around the cylinder bore 4, that is, around the cylinder liner 9, and as shown in FIG. The cylindrical parts are connected.
That is, the water jacket 6 is formed so as to open to the head mounting surface 3 side by the outer peripheral surface of the cylinder portion 5 and the outer peripheral wall surface formed so as to oppose the water jacket 6. That is, the cylinder block 1 of the present embodiment has an open deck type structure in which the water jacket 6 is opened to the head mounting surface 3 side. The water jacket 6 cools the cylinder bore 4 and the like through the cylinder portion 5.

  The cylinder block 1 of the present embodiment having the above-described configuration is configured to make the temperature of the bolt phase portion relatively higher than the other phase portions. The structure for lowering is provided. As such a configuration, in the cylinder block 1 of the present embodiment, the phase corresponding to the bolt fastening portion 10 by the head bolt 11 in the circumferential shape of the cylinder bore 4 in the surface of the bore forming portion 14 that receives the cooling action by the water jacket 6. Concave portions 21 and 22 are provided in the phase portion other than at least in the height range of the water jacket 6.

In the present embodiment, as the surface of the bore forming portion 14 that receives the cooling action by the water jacket 6, the outer peripheral surface of the cylinder portion 5 (hereinafter referred to as “cylinder portion outer peripheral surface”) that forms the water jacket 6 and directly contacts the cooling water 6 a. ) 15 and an outer peripheral surface of the cylinder liner 9 (hereinafter referred to as “liner outer peripheral surface”) 19 that receives the cooling action from the water jacket 6 via the cylinder portion 5. The concave portions 21 and 22 are provided on the cylinder portion outer peripheral surface 15 and the liner outer peripheral surface 19 respectively.
Therefore, as described above, when the cylinder bore 4 is formed directly on the structure of the cylinder block 1 without using the cylinder liner 9, the concave portion is provided only on the outer peripheral surface 15 of the cylinder portion. It will be.

The “phase” in the circumferential shape of the cylinder bore 4 (with respect to the circumferential shape) is as follows. That is, the cylinder bore 4, which is a cylindrical hole, has a circumferential shape when viewed in the central axis direction. In the circumferential shape of the cylinder bore 4 (as opposed to the circumferential shape), an angle on the circumference around the position of the central axis is determined. This angle (angle range) is a “phase” in the circumferential shape of the cylinder bore 4.
Therefore, the phase corresponding to the bolt fastening portion 10 by the head bolt 11 in the circumferential shape of the cylinder bore 4 is the position of the central axis when the cylinder bore 4 has a circumferential shape as shown in FIG. About the angle on the circumference centering on C, it becomes a predetermined angle range α1 in the direction including the bolt fastening portion 10 and the vicinity thereof from the center (position C). In the configuration in which four bolt fastening portions 10 are provided at substantially equal intervals around the cylinder bore 4 as in the present embodiment, the phase (angle range α1) corresponding to the bolt fastening portion 10 as described above has each cylinder bore. There will be 4 places in 4. And the said recessed parts 21 * 22 are provided in the part of phases other than the phase corresponding to such a bolt fastening part 10. FIG.
Hereinafter, the phase corresponding to the bolt fastening portion 10 by the head bolt 11 in the circumferential shape of the cylinder bore 4 is referred to as “bolt phase”, and the other phases (other phases) are referred to as “non-bolt phases”.

In the present embodiment, the recessed portions 21 and 22 provided in the portions of the non-bolt phase on each of the cylinder portion outer peripheral surface 15 and the liner outer peripheral surface 19 are configured by providing a plurality of grooves formed in the vertical direction. That is, the concave portion 21 provided on the outer peripheral surface 15 of the cylinder portion is constituted by a plurality of groove portions 21a extending in the vertical direction, and the concave portion 22 provided on the outer peripheral surface 19 of the liner is similarly extended in the vertical direction. It is comprised by the some groove part 22a.
The groove portion 21a provided on the outer peripheral surface 15 of the cylinder portion can be formed when the cylinder block 1 is cast or by processing such as cutting after the cylinder block 1 is cast. Further, the groove portion 22 a provided in the liner outer peripheral surface 19 is formed in a single product state of the cylinder liner 9 before being installed in the cylinder block 1 by cast-in. That is, the groove portion 22a can be formed when the cylinder liner 9 is a cast product, or by performing processing such as cutting after the cylinder liner 9 is formed by casting or the like.

Further, the recessed portions 21 and 22 provided on the cylinder outer peripheral surface 15 and the liner outer peripheral surface 19 are provided at least in the height range of the water jacket 6. That is, as in the present embodiment, in each of the concave portions 21 and 22 configured as the plurality of groove portions 21a and 22a formed in the vertical direction, the height of the groove portions 21a and 22a, that is, the length in the vertical direction. However, the concave portions 21 and 22 are configured to be at least substantially the same as the height of the water jacket 6, that is, the length in the vertical direction (depth with respect to the head mounting surface 3).
Therefore, with respect to the concave portion 21 provided on the cylinder portion outer peripheral surface 15 forming the water jacket 6, the groove portion 21 a is provided in substantially the entire vertical range of the cylinder portion outer peripheral surface 15. Further, for the concave portion 22 provided on the liner outer peripheral surface 19, the groove portion 22 a is provided in a range including the height range of the water jacket 6.

As described above, the cylinder liner 9 in the present embodiment is a cylindrical member that is made of cast iron and forms the cylinder bore 4 in the cylinder block 1. Of the outer peripheral surface (the liner outer peripheral surface 19), the non-bolt A concave portion 22 is provided in the phase portion at least in the height range of the water jacket 6.
That is, as shown in FIG. 3 and FIG. 4, in the cylinder liner 9 according to the present embodiment, the concave portion 21 is provided in the portion corresponding to the non-bolt phase in the state in which the cylinder block 1 is housed in the cast block or the like. It is done. Each concave portion 21 is constituted by a plurality of groove portions 21 a formed in the vertical direction as described above, and the groove portions 21 a are formed so that the length in the vertical direction is at least the height range of the water jacket 6. Is done.

  In this way, by providing the concave portions 21 and 22 on the surface of the bore forming portion 14 that receives the cooling action by the water jacket 6 and in the non-bolt phase portion, honing for the cylinder bore 4 of the cylinder block 1 is performed. Bore deformation that occurs during engine operation can be suppressed without increasing the number of processes during finishing, and deterioration of the roundness of the cylinder bore 4 during engine operation can be prevented.

That is, in the cylinder outer peripheral surface 15 and the liner outer peripheral surface 19, the non-bolt phase portion where the concave portions 21 and 22 are provided has a larger surface area per unit phase than the bolt phase portion, and the inside of the water jacket 6 is increased. Since cooling efficiency is improved in the bore cooling by the flowing cooling water 6a, the cooling is relatively strong. As a result, during engine operation, the temperature of the bolt phase portion is relatively increased with respect to the non-volt phase portion, and the temperature of the non-volt phase portion is higher than that in the case where the concave portions 21 and 22 are not provided. Become lower. Therefore, the thermal expansion of the bolt phase portion is relatively large with respect to the non-volt phase portion, and the thermal expansion of the non-volt phase portion is smaller than that in the case where the concave portions 21 and 22 are not provided. As a result, deterioration of the roundness of the cylinder bore 4 during engine operation is prevented.
Here, it will be described with reference to FIG. 5 that the roundness of the cylinder bore 4 is prevented from being deteriorated during engine operation. FIG. 5 is a schematic diagram showing the arrangement of the bolt fastening portion 10 with respect to the cylinder bore 4 and the bore deformation.

When the cylinder head 2 is assembled to the cylinder block 1, the tightening force by the head bolt 11 acts on the cylinder block 1, and assembly deformation occurs in the cylinder bore 4. In the configuration in which four bolt fastening portions 10 are provided at substantially equal intervals around the cylinder bore 4 as in this embodiment, this assembly deformation is a dotted line representing the shape of the cylinder bore 4 in the assembled and deformed state in FIG. As shown by B1, the deformation becomes a cross shape (quaternary deformation) (see FIG. 13B).
During engine operation, the temperature of the cylinder block 1 rises and the cylinder bore 4 expands in the circumferential direction. At this time, since the deformation of the bolt phase portion is suppressed by the bolt axial force due to the fastening of the head bolt 11, the portion of the non-bolt phase expands more than the portion of the bolt phase in the prior art. The cross shape due to the attached deformation is emphasized, and the roundness of the cylinder bore 4 is deteriorated (see FIG. 13C).

Therefore, as described above, by providing the concave portions 21 and 22 in the non-bolt phase portion, as shown in FIG. 5, the bolt fastening portion 10 is provided at four locations at substantially equal intervals around the cylinder bore 4. When the temperature of the bolt phase portion (see the solid line portion on the dotted line B1) within the predetermined angular range α1 centered on the center axis position C of the cylinder bore 4 is Tb, and the temperature of the non-bolt phase portion is T0. , Tb> T0 holds. Further, the temperature T0 of the non-volt phase portion is lower than that when the concave portions 21 and 22 are not provided.
For these reasons, the deformation (thermal deformation) of the cylinder bore 4 during actual operation of the engine increases the relative expansion amount of the bolt phase portion with respect to the non-bolt phase portion, and decreases the expansion amount of the non-bolt phase portion. As shown by a solid line B2 representing the shape of the cylinder bore 4 in a state of being thermally deformed in FIG. 5, the overall expansion in the circumferential direction of the cylinder bore 4 is made uniform. As a result, the deterioration of the roundness of the cylinder bore 4 at the time of actual engine operation is prevented, and the roundness is improved.

  Therefore, the magnitude of the angle of the predetermined angle range α1 with respect to the bolt phase is not particularly limited. However, the bolt phase is deformed (expanded) by the bolt axial force due to fastening of the head bolt 11 during thermal deformation during engine operation. ) Is set as an angle range corresponding to the portion to be suppressed.

Further, the number, size (width, depth, etc.), shape, and the like of the groove portions 21a and 22a of the concave portions 21 and 22 provided in the non-bolt phase portions are not particularly limited. The number of the groove portions 21a and 22a is appropriately set in consideration of the shape of the cylinder block 1, the relative positions of the plurality of cylinder bores 4 and the like. In other words, by adjusting the number of grooves 21a, 22a, etc., the water jacket can be adjusted according to the relative relationship between the plurality of cylinder bores 4 and the relative relationship between the bolt phase portion and the non-bolt phase portion. The degree of cooling by 6 can be adjusted.
Specifically, in the cylinder block 1, the portion between the adjacent cylinder bores 4 (between the bores) is a relatively high-temperature portion with respect to the other portion of the peripheral portion of the cylinder bore 4. For this reason, for example, in the groove portion 22a of the concave portion 22 provided on the liner outer peripheral surface 19 in the cylinder liner 9, the portion of the non-bolt phase that faces the portion between the bores, In comparison, the number of grooves 22a is increased. In the figure, with respect to the number of groove portions 22a of the concave portion 22 provided on the liner outer peripheral surface 19, there are five pairs of opposing non-bolt phases including a portion facing between the bores, whereas other non-bolt portions. There are three phase portions.
Further, for the concave portions 21 and 22 provided at least in the range of the height (vertical length) of the water jacket 6, for example, the concave portions 21 and 22 on the upper portion of the cylinder portion 5 and the cylinder liner 9 that are relatively hot. The number, size, shape, and the like of the concave portions 21 and 22 may be changed depending on the position in the vertical direction, such as by expanding the width.

Moreover, in this embodiment, although the recessed parts 21 and 22 provided in the part of a non-bolt phase are comprised by providing the several groove part 21a and 22a formed in an up-down direction, the shape which a surface area expands. If so, the configuration is not particularly limited.
That is, even when the concave portion provided in the non-bolt phase portion is constituted by a plurality of groove portions, the extending direction is not particularly limited, and in addition to the groove portions, a plurality of depression-like or hole-like portions are provided. The concave portion may be configured by, for example.

In the present embodiment, in the configuration in which the cylinder bore 4 is formed using the cylinder liner 9, the cylinder portion outer peripheral surface 15 and the liner outer peripheral surface included in the surface of the bore forming portion 14 that receives the cooling action by the water jacket 6. Although the concave portions 21 and 22 are provided in both 19, the configuration may be provided in only one of them.
At this time, as in the present embodiment, by providing the concave portions 21 and 22 on both the cylinder outer peripheral surface 15 and the liner outer peripheral surface 19, the cylinder bore is used when the engine is actually operated in the configuration in which the cylinder liner is used to form the cylinder bore. It is possible to effectively prevent the roundness of the steel from being deteriorated.

  A second embodiment of the cylinder block according to the present invention will be described with reference to FIGS. 6 is a cross-sectional view of the cylinder block according to the second embodiment of the present invention corresponding to the AA cross section in FIG. 1, FIG. 7 is a perspective view showing the cylinder liner according to the second embodiment of the present invention, and FIG. Similarly, FIG. 9 is a sectional view taken along the line CC in FIG. 8, and FIG. 10 is a partially enlarged explanatory view showing the principle of forming an air layer. In addition, about the part which is common in 1st embodiment mentioned above, the description is abbreviate | omitted suitably using the same code | symbol.

As shown in FIG. 6, the cylinder block 31 of the present embodiment has a configuration in which a main body is made of aluminum and the cylinder bore 4 is formed by a cylinder liner 29 made of cast iron.
The cylinder block 31 of the present embodiment is configured to increase the temperature of the bolt phase portion as a configuration for increasing the temperature of the bolt phase portion relative to other phase (non-volt phase) portions. Is provided. As such a configuration, in the cylinder block 31 of the present embodiment, the air layer 30 is provided in the bolt phase portion of the cylinder liner 29 at least in the height range of the water jacket 6.

The air layer 30 is constituted by a space formed in a cylindrical wall portion constituting the cylinder liner 29. The space constituting the air layer 30 is a hole that opens to one end face of the cylinder liner 29 (the face that faces the head mounting surface 3 in a state in which the cylinder liner 29 is housed in the cylinder block 31 by a fillet or the like). It is formed as a hollow portion that does not open to the outside of the cylinder liner 29.
In addition, the space constituting the air layer 30 may be one space portion that occupies the entire portion of each bolt phase or a plurality of spaces distributed in each bolt phase portion. .

When the cylinder liner 29 is a cast product, the air layer 30 can be formed by casting or using a collapsible core. The air layer 30 can also be formed by machining after the cylinder liner 29 is formed by casting or the like.
In this manner, the air layer 30 constituted by the space provided in the bolt phase portion of the wall portion of the cylinder liner 29 is provided at least in the height (vertical length) range of the water jacket 6. That is, the air layer 30 provided in the cylinder liner 29 is provided in a range including the height range of the water jacket 6 in each bolt phase portion.

As described above, the cylinder liner 29 in the present embodiment is made of cast iron and has a cylindrical shape that forms the cylinder bore 4 that opens to the head mounting surface 3 to which the cylinder head 2 is fixed by the head bolt 11 in the cylinder block 31. The air layer 30 is provided in the bolt phase portion at least in the height range of the water jacket 6.
In other words, in the cylinder liner 29 according to the present embodiment, the air layer 30 is provided in a portion corresponding to the bolt phase in a state in which the cylinder block 31 is housed in the cast block or the like. The air layer 30 is formed such that its vertical length (range) is at least the height range of the water jacket 6.

As described above, by providing the air layer 30 in the bolt phase portion of the cylinder liner 29, the same effect as that of the first embodiment can be obtained.
That is, in the cylinder liner 29, since the air layer 30 functions as a heat insulating layer, the bolt phase portion where the air layer 30 is provided is bored by the cooling water 6a flowing in the water jacket 6 with respect to the non-bolt phase portion. In cooling, since the cooling efficiency is lowered due to heat insulation, the cooling is relatively weak. As a result, during engine operation, the temperature of the bolt phase portion rises relative to the non-volt phase portion. Therefore, the thermal expansion of the bolt phase portion is relatively large with respect to the non-volt phase portion. As a result, deterioration of the roundness of the cylinder bore 4 during engine operation is prevented.

Specifically, in the cylinder block 31 of the present embodiment, deterioration of the roundness of the cylinder bore 4 during engine operation is prevented as follows.
As described above, during the engine operation, when the cylinder bore 4 expands in the circumferential direction, the deformation of the bolt phase portion is suppressed by the bolt axial force due to the fastening of the head bolt 11. This part expands greatly compared to the bolt phase part, the cross shape due to the assembly deformation is emphasized, and the roundness of the cylinder bore 4 is deteriorated (see FIG. 13C).

Therefore, by providing an air layer 30 in the bolt phase portion of the cylinder liner 29, as shown in FIG. 5, the bolt fastening portions 10 are provided at four locations at substantially equal intervals around the cylinder bore 4 as in the first embodiment. In the provided configuration, if the temperature of the bolt phase (angle range α1) portion (see the solid line portion on the dotted line B1) is Tb and the temperature of the non-volt phase portion is T0, the relationship Tb> T0 is established.
As a result, the deformation (thermal deformation) of the cylinder bore 4 during actual operation of the engine increases the relative expansion amount of the bolt phase portion with respect to the non-bolt phase portion, and the overall expansion in the circumferential direction of the cylinder bore 4 is uniform. It becomes. As a result, the deterioration of the roundness of the cylinder bore 4 at the time of actual engine operation is prevented, and the roundness is improved.

  The number, size (width, thickness, etc.), shape, etc. of the air layers 30 provided in each bolt phase portion of the cylinder liner 29 are not particularly limited. The number of such air layers 30 is appropriately set in consideration of the shape of the cylinder block 31 and the relative positions of the plurality of cylinder bores 4.

Then, the specific structure of the air layer 30 in this embodiment is demonstrated.
The air layer 30 according to the present configuration is made of a material that is cast into the cylinder liner 29 and has a smaller linear expansion coefficient (thermal expansion coefficient) than the material constituting the cylinder liner 29 (hereinafter referred to as “liner material”). When the space forming member 40 is cast into the cylinder liner 29, the space forming member 40 is configured by a space generated by a difference in cooling shrinkage between the liner material portion and the space forming member 40.

That is, in this configuration, the cylinder liner 29 is a cast product, and the space forming member 40 is cast when the cylinder liner 29 is cast.
As shown in FIGS. 7 to 9, the space forming member 40 is cast on the outer peripheral surface (liner outer peripheral surface 39) side of the cylinder liner 29, and the liner outer peripheral surface 39 which is a cylindrical surface in the cast state. Form a part of That is, in the cylinder liner 29 in which the space forming member 40 is cast, the original cylindrical shape is maintained.

As shown in FIGS. 7 to 9, the space forming member 40 has a space forming portion 41 configured by a plurality of plate-like portions 42.
The plate-like portion 42 constituting the space forming portion 41 is a plate-like portion along the cylindrical shape of the cylinder liner 20 so that the outer surface thereof forms a part of the liner outer peripheral surface 39, and the cylinder liner 29 is casted or the like. Thus, the cylinder block 31 is disposed so as to correspond to the bolt phase portion. In the configuration in which four bolt fastening portions 10 are provided at substantially equal intervals around the cylinder bore 4 as in the present embodiment, plate-like portions 42 are disposed at bolt phase portions corresponding to the respective bolt fastening portions 10. The That is, in this embodiment, the air layer 30 corresponding to one bolt phase portion in the cylinder liner 29 is configured by using one plate-like portion 42.

In addition, the space forming member 40 according to the present embodiment includes the connecting portion 43 for connecting the plurality of plate-like portions 42 constituting the space forming portion 41 as described above.
The connecting portion 43 is a portion configured in an annular shape (cylindrical shape), and connects a plurality of plate-like portions 42 at their lower end portions (right end portion in FIG. 8), and is arranged on the lower end side of the cylinder liner 29. The That is, the outer surface of the connecting portion 43 forms a part of the liner outer peripheral surface 39 together with the outer surface of the plate-like portion 42 on the lower end side of the cylinder liner 29 (below the space forming portion 41).
As described above, in the space forming member 40 of the present embodiment, the plurality of plate-like portions 42 constituting the space forming portion 41 are connected by the connecting portion 43, and the space forming member 40 is integrally configured as a whole. .

The space forming member 40 having such a configuration is cast when the cylinder liner 29 is cast. That is, in the casting apparatus for the cylinder liner 29, the casting is performed in a state where the space forming member 40 is set so that each plate-like portion 42 and the connecting portion 43 of the space forming portion 41 are in a predetermined position with respect to the cylinder liner 29. Is done. When the space forming member 40 is set in the casting apparatus, since the space forming member 40 is integrally formed by the connecting portion 43, good workability and productivity can be obtained.
For the casting of the cylinder liner 29 into which the space forming member 40 is cast, gravity casting in which the molten metal is supplied into the mold by its own weight is preferably used. However, the casting method of the cylinder liner 29 is not particularly limited.

  Thus, in the cylinder liner 29 cast with the casting of the space forming member 40, the space forming member 40 is made of a material having a smaller linear expansion coefficient than the liner material as described above. A difference occurs in the cooling shrinkage (thermal shrinkage due to cooling) between the liner material portion of the liner 29 and the space forming member 40. This difference in cooling shrinkage forms a space between each of the plate-like portions 42 constituting the space forming portion 41 of the space forming member 40 and the liner material portion. This space constitutes an air layer 30 provided in the bolt phase portion of the cylinder liner 29 (see FIGS. 6 and 9).

  That is, as shown in FIG. 10A, in the high temperature state after the release of the cylinder liner 29 in which the space forming member 40 is cast, a part of the liner outer peripheral surface 39 of the plate-like portion 42 is removed. The liner material is in contact with a portion other than the outer surface 42a to be formed. In other words, in the high temperature state of the cylinder liner 29, the plate-like portion 42 of the space forming member 40 is fitted to the concave portion 29 a existing on the outer peripheral side of the cylindrical wall portion constituting the cylinder liner 29 without a gap. It looks like.

Then, as shown in FIG. 10B, in the cooling process of the cylinder liner 29 from the high temperature state, in the plate-like portion 42 of the space forming member 40, the portion of the liner material in the cylinder liner 29 is more than the plate-like portion 42. Also contract (see arrow in the figure).
As a result, a space is formed between the bottom surface 29 b of the recess 29 a and the inner side surface 42 b of the plate-like portion 42. This space is used as what constitutes the air layer 30. Accordingly, the plate-like portion 42 is formed such that the length of the plate-like portion 42 in the vertical direction is the length of the air layer 30 in the vertical direction, and this length is at least the height range of the water jacket 6.

Since the space forming member 40 is a member cast into the cylinder liner 29, the material forming the space forming member 40 is a material that can be cast into the liner material, that is, a melting point sufficiently higher than the liner material. Is used.
Therefore, as a material constituting the space forming member 40, a material having a linear expansion coefficient smaller than that of the liner material and having a melting point high enough to be cast into the liner material is used.
Specifically, while the liner material is cast iron as in this embodiment, examples of the material forming the space forming member 40 include tungsten (W), titanium (Ti), and molybdenum (Mo). Can be mentioned. That is, the plate-like portion 42 of the space forming member 40 is configured as a low expansion metal plate made of tungsten or the like with respect to the cylinder liner 29 made of cast iron.

  Further, regarding the material constituting the space forming member 40, it is preferable to consider the level of thermal conductivity with respect to the liner material, thereby adjusting the heat insulation effect at the bolt phase portion where the air layer 30 is provided in the cylinder liner 29. can do. That is, for example, by using a material having lower thermal conductivity than the liner material as the material forming the space forming member 40, the heat insulation effect in the bolt phase portion of the cylinder liner 29 where the air layer 30 is provided can be enhanced. it can. Among the material examples, titanium corresponds to a material having a lower thermal conductivity than the liner material.

  In this manner, the air layer 30 provided in the bolt phase portion of the cylinder liner 29 is cast with the space forming member 40 made of a material having a smaller linear expansion coefficient than the liner material, and the liner material portion and the space forming member 40 are cast. By using a method of forming a space generated by a difference in cooling shrinkage from the (plate-like portion 42), the air layer 30 can be formed without subjecting the cylinder liner 29, which is a cast product, to mechanical processing or the like. It can be easily provided.

In the present embodiment, the air layer 30 is formed by using one plate-like portion 42 in each bolt phase portion of the cylinder liner 29. However, the present invention is not limited to this, and each bolt phase portion. The plate-like part 42 corresponding to may be constituted by a plurality of parts (a plurality of plate-like parts or the like).
For the air layer 30 provided at least in the range of the height (vertical length) of the water jacket 6, for example, the air layer 30 in the upper part of the cylinder liner 29 that is relatively high in temperature is configured to be thin. The thickness and size of the air layer 30 may be changed depending on the position. That is, the size and shape of the plate-like portion 42 are not particularly limited.

  A third embodiment of the cylinder block according to the present invention will be described with reference to FIGS. 11 and 12. FIG. 11 is a cross-sectional view showing a configuration of a cylinder block according to the third embodiment of the present invention, and FIG. 12 is a cross-sectional view taken along DD in FIG. In addition, about the part which is common in 1st embodiment mentioned above, the description is abbreviate | omitted suitably using the same code | symbol.

As shown in FIGS. 11 and 12, the cylinder block 51 of the present embodiment has a configuration in which the main body is formed of aluminum and the cylinder bore 4 is formed of a cylinder liner 49 formed of cast iron. ing.
The cylinder block 51 of the present embodiment is configured to increase the temperature of the bolt phase portion relative to the other phase (non-volt phase) portion, and to reduce the temperature of the non-volt phase portion. It has a configuration. As such a configuration, in the cylinder block 51 of the present embodiment, the material constituting the main body of the cylinder block 51 (hereinafter referred to as “block”) in the non-bolt phase portion of the cylinder portion 5 at least in the height range of the water jacket 6. Fins 61 made of a material having a higher thermal conductivity than that of “material” is provided.

As shown in FIGS. 11 and 12, the fin 61 is parallel to a surface in a vertical direction (hereinafter referred to as “horizontal direction”) with respect to the central axis direction of the cylinder bore 4 in the cylindrical wall-shaped portion constituting the cylinder portion 5. It is comprised as a plate-shaped part and has a shape along the cylindrical shape of the cylinder part 5. That is, the fin 61 is a plate-like portion having a substantially sector shape when viewed in the central axis direction of the cylinder bore 4 (see FIG. 12). Further, the fin 61 is provided in a state in which the fin 61 is housed in the cylinder part 5 of the cylinder block 51 or a part of the fin 61 is exposed from the cylinder part 5.
In the present embodiment, the substantially fan-shaped fins 61 are provided so as to occupy substantially the entire portion of each non-bolt phase in the cylinder portion 5 when the cylinder bore 4 shown in FIG. Therefore, as shown in FIG. 11, the outer surface of the fin 61 is exposed to the water jacket 6 side. Similarly, as shown in FIG. 11, depending on the height position (vertical position) where the fin 61 is provided, the upper surface of the fin 61 is exposed to the head mounting surface 3 side.

As shown in FIG. 12, in the present embodiment, the fins 61 provided at the four non-bolt phase portions with respect to one cylinder bore 4 are provided at the same height position in the vertical direction. That is, the four fins 61 are provided in the horizontal direction with respect to the non-bolt phase portion in the cylinder portion 5. As shown in FIG. 11, the fins 61 provided at the same height as described above are provided in a plurality of stages at appropriate intervals in the vertical direction in the cylinder portion 5.
A plurality of fins 61 provided in the horizontal direction and the vertical direction are provided at least within the height (length in the vertical direction) range of the water jacket 6. That is, the plurality of fins 61 provided in the cylinder portion 5 are arranged in a range including the height range of the water jacket 6 in each non-bolt phase portion.

As described above, in the cylinder portion 5 formed around one cylinder bore 4, the plurality of fins 61 provided in the horizontal direction and the vertical direction are provided around the cylindrical base portion 62 that can be fitted on the cylinder liner 49. It becomes a state.
That is, the plurality of fins 61 are formed so as to protrude from the outer peripheral surface of the cylindrical base portion 62, and the plurality of fins 61 and the base portion 62 are configured as an integral fin member 60.

Then, the fin member 60 having the fins 61 arranged in a predetermined state around the base portion 62 is cast together with the cylinder liner 49 when the cylinder block 51 is cast. In other words, in the cylinder block 51 of the present embodiment, the cylinder bore 4 is formed by the cylinder liner 49 being installed on the inner peripheral surface side of the cylinder portion 5 by a caster. The fin member 60 is externally fitted to the cylinder liner 49 cast around the cylinder block 51.
Specifically, the outer peripheral surface (liner outer peripheral surface 59) of the cylinder liner 49 and the inner peripheral surface 63 of the base portion 62 of the fin member 60 both have a cylindrical shape, and have substantially the same diameter. The fin member 60 is externally fitted by press fitting or the like. The cylinder liner 49 in a state of being integrated with the fin member 60 by this external fitting is cast when the cylinder block 51 is cast. As a result, the plurality of fins 61 are disposed in the cylinder portion 5 in the cylinder block 51.

Since the fin member 60 constituting the fin 61 is a member cast around the cylinder block 51, the material constituting the fin member 60 is a material that can be cast against the block material, that is, a block material. Also, those having a sufficiently high melting point are used.
Therefore, as the material constituting the fin member 60 (fin 61), a material having a higher thermal conductivity than the block material and a melting point high enough to be cast with respect to the block material is used.
Specifically, the block material is aluminum as in the present embodiment, but examples of the material constituting the fin member 60 include copper (Cu).

Thus, the effect similar to 1st embodiment can be acquired by providing the fin 61 in the part of the non volt | bolt phase in the cylinder part 5. FIG.
That is, in the cylinder portion 5, the non-volt phase portion where the fins 61 are provided has higher thermal conductivity than the bolt phase portion, and the cooling efficiency is improved in the bore cooling by the cooling water 6 a flowing in the water jacket 6. Therefore, it is relatively strongly cooled. As a result, during engine operation, the temperature of the bolt phase portion is relatively increased with respect to the non-volt phase portion, and the temperature of the non-volt phase portion is lower than when the fins 61 are not provided. . Accordingly, the thermal expansion of the bolt phase portion is relatively large with respect to the non-volt phase portion, and the thermal expansion of the non-volt phase portion is smaller than that in the case where the fins 61 are not provided. As a result, deterioration of the roundness of the cylinder bore 4 during engine operation is prevented.

In addition, about the fin 61 provided in the non-bolt phase part in the cylinder part 5, the number (one in this embodiment) and size (thickness / horizontal direction) provided in the same height position in one non-bolt phase part And the like are not particularly limited. The number of the fins 61 and the like are appropriately set in consideration of the shape of the cylinder block 51 and the relative positions of the plurality of cylinder bores 4.
In addition, with regard to the fins 61 that are provided in a plurality of stages at appropriate intervals within at least the height (length in the vertical direction) of the water jacket 6, for example, the vertical fins 61 in the upper part of the cylinder portion 5 that are relatively hot. The interval and size of the fin 61 in the vertical direction may be changed depending on the position in the vertical direction. As shown in FIG. 11, in the drawing, the vertical spacing of the fins 61 is gradually narrowed toward the upper side of the cylinder portion 5. Further, the fin 61 may have a single stage (integrated in the vertical direction) without being arranged in a plurality of stages in the vertical direction.

Further, as shown in FIG. 12, in a multi-cylinder engine, the cylinder portion 5 provided for the adjacent cylinder bores 4 is in a state where cylindrical wall portions are connected between the bores. About the fin 61 provided in the part of the non-bolt phase which becomes the part between the bores of the cylinder part 5, the configuration in which the fins 61 provided for the adjacent cylinder parts 5 are arranged at different height positions, or the same A configuration or the like having a shape that does not interfere with each other at the height position is appropriately used, and interference between the fins 61 can be avoided.
Similarly, in a multi-cylinder engine, the fin members 60 that are externally fitted to the cylinder liners 49 that form the cylinder bores 4 are integrally formed, so that the fins 61 interfere with each other at the portion between the bores of the cylinder portion 5. It is considered that the productivity of the cylinder block 51 can be improved.

Sectional drawing which shows the structure of the cylinder block which concerns on 1st embodiment of this invention. AA sectional drawing in FIG. The figure which shows the cylinder liner which concerns on 1st embodiment of this invention. BB sectional drawing in FIG. The schematic diagram which shows arrangement | positioning of a bolt fastening part with respect to a cylinder bore, and a bore deformation | transformation. Sectional drawing equivalent to the AA cross section in FIG. 1 of the cylinder block which concerns on 2nd embodiment of this invention. The perspective view which shows the cylinder liner which concerns on 2nd embodiment of this invention. Similarly side view. CC sectional drawing in FIG. Partial enlarged explanatory drawing which shows the formation principle of an air layer. Sectional drawing which shows the structure of the cylinder block which concerns on 3rd embodiment of this invention. DD sectional drawing in FIG. The schematic diagram which shows arrangement | positioning of the bolt fastening part with respect to a cylinder bore, and conventional bore deformation | transformation.

Explanation of symbols

1 Cylinder block 2 Cylinder head 3 Head mounting surface (Cylinder head mounting surface)
4 Cylinder bore 5 Cylinder part 6 Water jacket 7 Piston 9 Cylinder liner 10 Bolt fastening part (fastening part)
11 Head bolt (fastening member)
14 bore forming portion 15 cylinder outer peripheral surface 19 liner outer peripheral surface 21 concave portion 22 concave portion 29 cylinder liner 30 air layer 31 cylinder block 40 space forming member 42 plate portion 51 cylinder block 61 fin

Claims (8)

Cylinder bore that is a cylindrical hole that opens to a cylinder head mounting surface to which the cylinder head is fixed by a fastening member and slidably mounts a piston, and a bore forming portion that includes a cylinder portion that is a wall-like portion surrounding the cylinder bore A water jacket formed so as to surround the cylinder bore via a cylinder block,
Of the surface of the bore forming portion that receives the cooling action by the water jacket, in the phase portion other than the phase corresponding to the fastening portion by the fastening member in the circumferential shape of the cylinder bore,
A cylinder block comprising a concave portion at least in a height range of the water jacket. The cylinder bore is formed by a cylindrical cylinder liner,
The cylinder block according to claim 1, wherein an outer peripheral surface of the cylinder liner is included on a surface of the bore forming portion that receives the cooling action. A cylinder bore that is a cylindrical hole that is formed by a cylindrical cylinder liner and opens to a cylinder head mounting surface to which the cylinder head is fixed by a fastening member, and the cylinder bore that is a wall portion that surrounds the cylinder bore. A water jacket formed so as to surround the cylinder block,
In the portion of the phase corresponding to the fastening portion by the fastening member in the circumferential shape of the cylinder bore of the cylinder liner,
A cylinder block comprising an air layer at least in a height range of the water jacket. The air layer is
A space forming member made of a material having a smaller linear expansion coefficient than a material constituting the cylinder liner, which is cast into the cylinder liner, is cast into the cylinder liner, so that a portion of the material constituting the cylinder liner The cylinder block according to claim 3, wherein the cylinder block is formed by a space generated by a difference in cooling contraction between the space forming member and the space forming member. A cylinder bore that is a cylindrical hole that opens in a cylinder head mounting surface to which the cylinder head is fixed by a fastening member and slidably houses a piston, and a cylinder portion that is a wall portion surrounding the cylinder bore, and the cylinder bore A water jacket formed so as to surround the cylinder block,
Of the cylinder part, in the part of the phase other than the phase corresponding to the fastening part by the fastening member in the circumferential shape of the cylinder bore,
A cylinder block comprising a fin made of a material having a higher thermal conductivity than a material constituting a main body of the cylinder block at least in a height range of the water jacket. A cylindrical cylinder liner that forms a cylinder bore that opens to a cylinder head mounting surface to which a cylinder head is fixed by a fastening member in a cylinder block,
Of the outer peripheral surface, in the portion of the phase other than the phase corresponding to the fastening portion by the fastening member in the circumferential shape of the cylinder bore,
A cylinder liner comprising a concave portion at least in a height range of the water jacket. A cylindrical cylinder liner that forms a cylinder bore that opens to a cylinder head mounting surface to which a cylinder head is fixed by a fastening member in a cylinder block,
In the portion of the phase corresponding to the fastening portion by the fastening member in the circumferential shape of the cylinder bore,
A cylinder liner, wherein an air layer is provided at least in a height range of the water jacket. The air layer is
A space forming member made of a material having a smaller linear expansion coefficient than a material constituting the cylinder liner, which is cast into the cylinder liner, is cast into the cylinder liner, so that a portion of the material constituting the cylinder liner The cylinder liner according to claim 7, wherein the cylinder liner is configured by a space generated by a difference in cooling shrinkage between the space forming member and the space forming member.

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